If you are looking to save a little money in your budget next year, try http://www.doccop.com/ as an alternative to the forensic Turnitin. This free tool does not have all the bells and whistles that Turnitin.com has, but serves as an instructional tool for students to self-assess their work. Why not "teach them to fish" for plagiarism, rather than policing it yourself? You could even package this as verbiage stalking or research surveillance and the students might drink the coolade. It might even be fun to have the students peer review for plagiarism and and award papers an affidavit of authenticity. This is not to substitute for a lesson on giving credit where credit is due, but is just another tool for your toolbox.
Years ago, I remember reading a report written by 8th grade Eddie. It was a beautiful biographical synopsis of his favorite guitar player... So beautiful, that we knew Eddie did not compose it. Now Eddie might have been able to play the guitar beautifully, but he could not write a report. A simple check provided us the source of his narrative wonder. Eddie did not understand plagiarism. In fact, Eddie did not understand writing.
Carol Simpson, one of the leading voices on digital ethics, recommends this tool as well as Turnitin.
What this product does is:
* allows a submission of about 500 words to be checked.
* breaks up the submission into 500 successive "strings" of words
* Searches the web for each of the 500 strings
I tested DocCop with some original work and found that not one string was plagiarized. Then, I copied some wording from an article I wrote that is out on the web, and it found a few instances of phrases quoted from the article along with similarly worded phrases that were close to "common knowledge." So, it does find the match.
This tool may not search the "deep web" but rather uses Bing to search the surface web. This does not compare to the archived data within Turnitin, which is likely to have sources quoted from numerous databases, but at least it's a start. Whether you are librarian or a classroom teacher, the CCSS say we should be teaching students to research and write, "while avoiding plagiarism." [CCSS, ELA Anchor Standard 8] At least we can search through the garbology of the web.
Carol Simpson puts it nicely when she shares this quote in a PPT: "We are living in a world of nuclear giants and ethical infants." This might be an uphill battle, but it's a battle worth the scrimmage. After all, these students are tomorrow's society and there's no shortcut to success.